【速報】 IEEE EMBC2013

IEEE EMBC2013大阪中之島の国際会議場で開催されました。
研究室からは、M1の中村さんがICAと加速度センサを用いたfNIRSデータに対する体動除去手法 というタイトルで発表しました。
特別講演でiPS細胞の山中教授の講演が予定されていましたが、ビデオでした。残念。

学会参加報告書

 報告者氏名 中村友香
発表論文タイトル ICAと加速度センサを用いたfNIRSデータに対する体動除去手法
発表論文英タイトル Method for Removing Motion Artifacts from fNIRS Data Using ICA and an Acceleration Sensor
著者 廣安知之,中村友香,横内久猛
主催 IEEE EMBC,JSMBE
講演会名 IEEE EMBC2013
会場 大阪国際会議場
開催日程 2013/07/03-2013/07/07
 

 
1. 講演会の詳細
2013/07/03から2013/07/07にかけて,大阪国際会議場にて開催されましたIEEE EMBC2013に参加いたしました.このEMBC2013は,IEEE EMBC(http://www.embs.org/)によって主催された講演会で今年度は,JSMBE(http://jsmbe.org/index-en.html)によって主催される日本生体医工学会大会と併催されていました.この講演会は,医療に関して,生体工学や科学,情報システムなどを応用し,医学の分野に貢献することを目的に開催されています.
私は4,5,6,7日のみ参加いたしました.本研究室からは他に廣安先生が参加されました.
 
2. 研究発表
2.1. 発表概要
私は7日の8:00からのセッション「Blind Source Separation and Independent Component AnalysisⅠ」に参加いたしました.発表の形式は口頭発表で,12分の講演時間と3分の質疑応答時間となっておりました.
今回の発表は,卒業論文で発表した内容を英語でまとめたものです.以下に抄録を記載致します.

ICA (independent component analysis) is one of the most preferred methods for removing motion artifacts from the fNIRS (functional near-infrared spectroscopy) data.  In this method, the component derived from a motion artifact is removed by comparing the acceleration sensor data and the signal, which was separated by ICA.  However, because of the influence of blood flow, fNIRS data is often delayed in time compared to the acceleration sensor data.  For this reason, the correlation is reduced and it is difficult to identify whether the component has been derived from the motion artifact.  In this paper, we propose a method to remove the motion artifact using ICA, which takes into account the time delay in fNIRS data.  In this proposed method, ICA is executed multiple times, shifting the start time of fNIRS data each time.  Then, only the best correlated result is adopted to compare with the acceleration sensor data.  In order to examine the effectiveness of the proposed method, the execution results of the proposed method are compared with the results obtained, without considering the time delay.  It is found that, the accuracy of removing the motion artifact is improved by the proposed method.

 
2.2. 質疑応答
今回の講演発表では,質疑がありませんでした.
 
2.3. 感想
はじめての学会であり,さらに国際学会であったこともあり,とても緊張しました.発表は,時間内に終わることもできたので,うまく発表出来たのではないかと思います.質問が何もなかったのはとても残念でした.しかし,セッション終了後に話しかけていただけました.また,welcome receptionで知り合った人たちが聞きに来てくれていたり,感想を聞きに来てくれたり,研究についてディスカッションしようと言ってもらえたり,手法や論文等を教えていただけたりしました.山中教授の話をはじめ,様々な研究発表や話を聞くことができ,外国の人と仲良くなれ,とても勉強になったし,楽しく充実した時間を過ごすことができたと思います.次回学会に参加する際にはもう少し英語を話せるようになっていたいと思いました.
 
3. 聴講
今回の講演会では,下記の4件の発表を聴講しました.
 

発表タイトル          :Developing Stimulus Presentation on Mobile Devices for a Truly

Portable SSVEP-based BCI

著者                     : Yu-Te Wang, Yijun Wang, Chung-Kuan Cheng, and Tzyy-Ping Jung

セッション名       :Brain-computer Interface III

Abstract :  This study integrates visual stimulus presentation and near real-time data processing on a mobile device (e.g. a Tablet or a cell-phone) to implement a steady-state visual evoked potentials (SSVEP)-based brain-computer interface (BCI). The goal of this study is to increase the practicability, portability and ubiquity of an SSVEP-based BCI for daily use. The accuracy of flickering frequencies on the mobile SSVEP BCI system was tested against that on a laptop/desktop used in our previous studies. This study then analyzed the power spectrum density of the electroencephalogram signals elicited by the visual stimuli rendered on the mobile BCIs. Finally, this study performed an online test with the Tablet-based BCI system and obtained an averaged information transfer rate of 33.87 bits/min in three subjects. The current integration leads to a truly practical and ubiquitous SSVEP BCI on mobile devices for real-life applications.

この研究では,SSVEPベースのBCIをモバイルデバイス上で実装し,リアルタイム処理を行うというものでした.BCIが身近なモバイルデバイスで使用できるようになるまで発展していることに驚きました.
 

発表タイトル          : Independent Component Analysis of EEG-fMRI data for studying epilepsy and epileptic seizures

著者                  : Tiziana Franchin, Maria G. Tana, Vittorio Cannatà, Sergio Cerutti, and Anna M. Bianchi
セッション名       : Multimodal Blind Source Separation: Algorithms, Applications and Future Challenges
Abstruct            : Here we present a method for classifying fMRI independent components (ICs) by using an optimized algorithm for the individuation of noisy signals from sources of interest. The method was applied to estimate brain activations fromcombined EEG‐fMRI data for the exploration of epilepsy.  Spatial ICA was performed using the above-mentioned optimized algorithm and other three popular algorithms. ICs were sorted considering the value: of the coefficients of determination R2, obtained from the multiple regression analysis with morphometric maps of cerebral matter; of thekurtosis, which features the signal energy. The validation of the method was performed comparing the brain activations obtained with those resulted using the General Linear Model (GLM). The ICA‐derived activations in different datasets comprised subareas of the GLM‐revealed activations, even if the volume and the shape of activated areas do not correspond exactly. The method proposed also detects additional negative regions implicated in a default mode of brain activity, and not clearly identified by GLM. Compared with a traditional GLM approach, the ICA one provides a flexible way to analyze fMRI data that reduces the assumptions placed upon the hemodynamic response of the brain and the temporal constrains.

この発表では,てんかんの研究のためにEEG-fMRIデータにICAを用いるというものでした.様々なICAアルゴリズムが用いられており,その中でもFastICAとoptimized RobustICAが良いとされていました.
 

発表タイトル       :Cortical Activation Pattern for Grasping During Observation, Imagery, Execution, FES, and Observation-FES Integrated BCI : An Fnirs Pilot Study著者                  : An Jinung, Jin SangHyeon, Lee Seung Hyun, Jang GwangHee, Abibullaev Berdakh, Lee Hyun Ju, Moon Jeon Il
セッション名       : Brain Functional Imaging II
Abstract            :  Passive movement, action observation and motor imagery as well as motor execution have been suggested to facilitate the motor function of human brain. The purpose of this study is to investigate the cortical activation patterns of these four modes using a functional near-infrared spectroscopy (fNIRS) system. Seven healthy volunteers underwent optical brain imaging by fNIRS. Passive movements were provided by a functional electrical stimulation (FES). Results demonstrated that while all movement modes commonly activated premotor cortex, there were considerable differences between modes. The pattern of neural activation in motor execution was best resembled by passive movement, followed by motor imagery, and lastly by action observation. This result indicates that action observation may be the least preferred way to activate the sensorimotor cortices. Thus, in order to show the feasibility of motor facilitation by a brain computer interface (BCI) for an extreme case, we paradoxically adopted the observation as a control input of the BCI. An observation-FES integrated BCI activated sensorimotor system stronger than observation but slightly weaker than FES. This limitation should be overcome to utilize the observation-FES integrated BCI as an active motor training method.

この研究では,fNIRS装置を利用し,運動イメージやFESなど4種類の脳の活性化パターンの検討が行われていました.BCIでfNIRSが用いられているのはめずらしいと感じました.EEGではなく,fNIRSを用いた理由を質問すると,ノイズが少ないからと答えられていました.精度向上が今後の課題だそうです.
 

発表タイトル          :Evaluation of Classifier Topologies for the Real-time Classification of Simultaneous Limb Motions

著者                  : Max Ortiz-Catalan, Rickard Brånemark, and Bo Håkansson
セッション名       :EMG Models and Processing

Abstract :  The prediction of motion intent through the decoding of myoelectric signals has the potential to improve the functionally of limb prostheses. Considerable research on individual motion classifiers has been done to exploit this idea. A drawback with the individual prediction approach, however, is its limitation to serial control, which is slow, cumbersome, and unnatural. In this work, different classifier topologies suitable for the decoding of mixed classes, and thus capable of predicting simultaneous motions, were investigated in real-time. These topologies resulted in higher offline accuracies than previously achieved, but more importantly, positive indications of their suitability for real-time systems were found. Furthermore, in order to facilitate further development, benchmarking, and cooperation, the algorithms and data generated in this study are freely available as part of BioPatRec, an open source framework for the development of advanced prosthetic control strategies.

この研究では,筋電信号から運動意図を予測し,義手のさまざまなパターンの動きをリアルタイムで制御できるためのアルゴリズムが開発されていました.実際に義手が動いている動画はスムーズですごいと感じました.
 
参考文献
1)    35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society in conjunction with 52nd Annual Conference of Japanese Society for Medical and Biological Engineering (JSMBE) , http://embc2013.embs.org/